The proposed invention relates to medicine, in particular to surgical dentistry, and can be used for forming a bone bed for the placement of an implant.
Cylindrical and conical dental bone mills, (RU 2,251,391), for forming a bone bed for the placement of an implant, which include a tail part and cutting parts, are known. The cutting part has cutting edges of a straight shape and depressions. The depressions form an angle 60-90° therebetween. As a result, bone chip accumulation takes place. The mills are composed of tool steel or stainless steel, as a rule, with a subsequent anticorrosion coating with a titanium nitrate, which is a pronounced allergen. However, the coating has low strength and is worn relatively quickly during the operation process (i.e., low tribological properties). With cyclical loads, rapid destruction of the anticorrosion coating takes place, as well as contamination of the surface of the implant bed due to the metal from which the mill is produced. This often leads to destruction of the osteointegration process and causes post-operative complications.
Another problem of bone bed forming dental instruments is their heating at high rotary speeds (up to 1000 rev/min), which can cause a risk of thermal burn of the bone tissues of a patient. In order to reduce the risk of the thermal burn, the drill disclosed in RU Patent No. 2,151,570, includes a cylindrical body having a tail part, a working part with chutes, and cutting edges, as well as, channels formed with variable diameter inside the cylindrical body. Analogous solutions to reduce the risk of the thermal burn are disclosed in U.S. Pat. Nos. 5,575,651, 5,261,818, and German Patent No. 2,331,023. The provision of a uniform and constant flow of cooling liquid, for example water, provides significant reduction of the possibility of thermal injury to the treated bone tissue.
A high speed of rotation of a bone drilling instrument can also cause uncontrolled removal of material, depending on the force applied to the head. The invention disclosed in RU Patent No. 2,019,151 is directed to increasing treatment safety and simplification of construction. The drill operates at a high rotary speed, at or greater than 800 rev/min, which is disadvantageous. The tool provides removal of material in a dosed manner, during a single revolution, by a value not more than a height of the extension of the cutting element above the support, which does not allow for deeper penetration. The head and neck parts are composed of metal, while the cutting element has a diamond coating. Another disadvantage of this instrument is due to insufficient reliability caused by the rapid wearing of the coating, which is the result of crumbling of the ultra-dispersed diamonds of the cutting element.
The closest technical solution to the present proposal is a bone mill for an implant in accordance with the U.S. Pat. No. 6,659,769, which contains a tail part, a connecting neck, and a head with cutting elements formed as a plate of rotation. This construction partially resolves the problem of overheating and provides a removal of a bone chip. The disadvantage of this bone mill is that in its construction there is no limiting element for controlled removal of bone tissue. In addition, during an operation, the conical or cylindrical shape of the mill results in constant contact of the mill with the treated bone, which risks the possibility of thermal burn of the bone tissue.
What is needed is a device for forming a bone bed for dental implants having increased strength and wear-resistance, controlled removal of bone tissue, reduced risk of thermal burn to the bone tissues, as well as, a bone bed forming device having a surface corresponding to the surface of the implant.